A tan metal gutter downspout resting loosely inside a white plastic drain pipe adapter on the ground, with an open, unsealed gap around it, surrounded by pine straw and mulch.
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A tan metal gutter downspout resting loosely inside a white plastic drain pipe adapter on the ground, with an open, unsealed gap around it, surrounded by pine straw and mulch.

At this McKinney home, the gutter downspout drops into a white plastic drain pipe adapter with an open, unsealed gap around it. A mouse needs a gap no wider than a pencil and a rat one about the size of a quarter, so this opening can give rodents a sheltered route into the drain line and toward the house. Rodent proofing closes gaps like this with metal mesh or flashing so rainwater still drains while pests are kept out.